JP2000138599A - Transmission circuit - Google Patents
Transmission circuitInfo
- Publication number
- JP2000138599A JP2000138599A JP10308931A JP30893198A JP2000138599A JP 2000138599 A JP2000138599 A JP 2000138599A JP 10308931 A JP10308931 A JP 10308931A JP 30893198 A JP30893198 A JP 30893198A JP 2000138599 A JP2000138599 A JP 2000138599A
- Authority
- JP
- Japan
- Prior art keywords
- amplifier
- voltage
- gain
- current
- circuit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/02—Transmitters
- H04B1/04—Circuits
- H04B1/0475—Circuits with means for limiting noise, interference or distortion
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Transmitters (AREA)
- Control Of Amplification And Gain Control (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、CDMA方式の携
帯電話機等に使用される送信回路に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission circuit used for a CDMA type portable telephone or the like.
【0002】[0002]
【従来の技術】携帯電話機は送信回路と受信回路とを有
して基地局との間で送受信を行い、基地局を介して加入
者間が通話する。その際、基地局から携帯電話機に送信
される送信信号のレベルは常に一定であるので、携帯電
話機で受信した信号のレベルは基地局と携帯電話機との
距離によって変わる。また、基地局は携帯電話機から出
力された信号を常に一定のレベルで受信するようになっ
ている。2. Description of the Related Art A portable telephone has a transmitting circuit and a receiving circuit for transmitting and receiving data to and from a base station, and a subscriber talks through the base station. At this time, since the level of the transmission signal transmitted from the base station to the mobile phone is always constant, the level of the signal received by the mobile phone varies depending on the distance between the base station and the mobile phone. The base station always receives a signal output from a mobile phone at a constant level.
【0003】そのため、携帯電話機における受信回路お
よび送信回路は大きなダイナミックレンジが必要とな
り、また、受信回路では基地局からのパワーコントロー
ル信号に基づく自動利得制御電圧によって内部の増幅器
の利得が制御されるとともに、この自動利得制御電圧に
基づいて、送信回路から基地局に送信する送信信号のレ
ベルを変えるようにしている。For this reason, a receiving circuit and a transmitting circuit in a portable telephone require a large dynamic range. In the receiving circuit, the gain of an internal amplifier is controlled by an automatic gain control voltage based on a power control signal from a base station. The level of the transmission signal transmitted from the transmission circuit to the base station is changed based on the automatic gain control voltage.
【0004】従来の送信回路を図4乃至図6に従って説
明する。先ず、図4において、QPSK変調された20
0MHz帯の中間周波信号IFは図示しない変調器から
出力されて中間周波増幅器21に入力される。中間周波
増幅器21は利得制御が可能な可変利得増幅器で構成さ
れ、その利得は基地局からのパワーコントロール信号に
基づく自動利得制御電圧Vによって制御される。自動利
得制御電圧Vは3.0ボルトから0ボルトまで変化し、
図5の曲線Aに示すように、最大利得からおよそ60d
Bまで減衰するように制御される。中間周波信号IFは
中間周波増幅器21によって増幅された後、混合器22
aと局部発振器22bとで構成される周波数変換器22
に入力される。中間周波信号IFは混合器22aにおい
て、局部発振器22bから出力される局部発振信号と混
合されておよそ1.1GHz帯の送信信号RFに周波数
変換される。A conventional transmission circuit will be described with reference to FIGS. First, in FIG. 4, the QPSK-modulated 20
The intermediate frequency signal IF in the 0 MHz band is output from a modulator (not shown) and input to the intermediate frequency amplifier 21. The intermediate frequency amplifier 21 is constituted by a variable gain amplifier capable of gain control, and the gain is controlled by an automatic gain control voltage V based on a power control signal from a base station. The automatic gain control voltage V changes from 3.0 volts to 0 volts,
As shown by curve A in FIG.
It is controlled to attenuate to B. The intermediate frequency signal IF is amplified by the intermediate frequency amplifier 21 and then mixed by the mixer 22.
frequency converter 22 composed of a and a local oscillator 22b
Is input to The intermediate frequency signal IF is mixed in the mixer 22a with the local oscillation signal output from the local oscillator 22b, and frequency-converted into a transmission signal RF in a band of about 1.1 GHz.
【0005】送信信号RFは、先ず、高周波増幅器(R
F増幅器という)23で増幅される。RF増幅器23も
利得制御が可能な可変利得増幅器で構成され、その利得
は自動利得制御電圧Vによって制御され、図5の曲線B
に示すように、最大利得からおよそ30dBまで減衰す
るようになっている。従って、中間周波増幅器21とR
F増幅器23による全体の利得減衰量は図5の曲線Cに
示すように、90dB確保できる。RF増幅器23で増
幅されたRF信号は駆動増幅器(ドライバ増幅器とい
う)24でさらに増幅される。ドライバ増幅器24は次
段の電力増幅器25を十分に駆動できるレベルまでRF
信号を増幅するためのものである。そして、ドライバ増
幅器24によって増幅されたRF信号は電力増幅器25
によって所定の送信レベルまで増幅され、アンテナ26
から基地局に向けて送信される。A transmission signal RF is first supplied to a high-frequency amplifier (R
(Referred to as an F amplifier) 23. The RF amplifier 23 is also constituted by a variable gain amplifier whose gain can be controlled, the gain of which is controlled by the automatic gain control voltage V.
As shown in FIG. 7, the signal is attenuated from the maximum gain to about 30 dB. Therefore, the intermediate frequency amplifier 21 and R
As shown by a curve C in FIG. 5, 90 dB can be secured for the entire gain attenuation by the F amplifier 23. The RF signal amplified by the RF amplifier 23 is further amplified by a drive amplifier (referred to as a driver amplifier) 24. The driver amplifier 24 operates at RF level until the power amplifier 25 of the next stage can be driven sufficiently.
This is for amplifying the signal. The RF signal amplified by the driver amplifier 24 is
Is amplified to a predetermined transmission level by the antenna 26
Transmitted to the base station.
【0006】ドライバ増幅器24は二つのトランジスタ
7a、7bを有する差動増幅回路7で構成される。トラ
ンジスタ7a、7bのエミタ同士は共通の抵抗7cによ
ってグランドに接続され、コレクタにはそれぞれ負荷抵
抗7d、7eを介して電圧Bが供給される。そして、R
F増幅器23で増幅された送信信号RFがベース間に入
力され、増幅された送信信号RFがコレクタ間から出力
される。The driver amplifier 24 is constituted by a differential amplifier circuit 7 having two transistors 7a and 7b. The emitters of the transistors 7a and 7b are connected to ground by a common resistor 7c, and the collector is supplied with the voltage B via load resistors 7d and 7e, respectively. And R
The transmission signal RF amplified by the F amplifier 23 is input between the bases, and the amplified transmission signal RF is output from between the collectors.
【0007】[0007]
【発明が解決しようとする課題】以上説明した従来の送
信回路では、周波数の低い中間周波信号IFを増幅する
中間周波増幅器21の利得は周波数の高い送信信号RF
を増幅するRF増幅器23の利得よりも高い(ほぼ2
倍)ので、全体の利得減衰量を分担する中間周波増幅器
21とRF増幅器23との割合が自動利得制御電圧Vの
変化範囲内(3.0ボルト〜0ボルト)で平均的におよ
そ2対1となっている。しかも、RF増幅器23は周波
数の高い信号を増幅するため、自動利得制御電圧Vが高
くなると利得が飽和する。その結果、自動利得制御電圧
Vの高い範囲(例えば3.0ボルト〜1.5ボルト)で
は、全体の利得減衰量に占める中間周波増幅器21の利
得減衰量の割合がより大きくなって(2/3以上)S/
Nが悪化していた。また、出力電力を中電力または低電
力とする自動利得制御電圧Vの低い範囲(例えば1.5
ボルト〜0ボルト)でも、全体の利得減衰量に占める中
間周波増幅器21の利得減衰量の割合が大きい(ほぼ2
/3以上)ので、C/Nが悪化していた。In the conventional transmission circuit described above, the gain of the intermediate frequency amplifier 21 for amplifying the intermediate frequency signal IF having a low frequency is equal to that of the transmission signal RF having a high frequency.
Is higher than the gain of the RF amplifier 23 (approximately 2
Therefore, the ratio of the intermediate frequency amplifier 21 and the RF amplifier 23 which share the entire gain attenuation is about 2 to 1 on average within the change range of the automatic gain control voltage V (3.0 to 0 volts). It has become. In addition, since the RF amplifier 23 amplifies a signal with a high frequency, the gain is saturated when the automatic gain control voltage V increases. As a result, in the high range of the automatic gain control voltage V (for example, 3.0 volts to 1.5 volts), the ratio of the gain attenuation of the intermediate frequency amplifier 21 to the total gain attenuation becomes larger (2 / 3 or more) S /
N was getting worse. In addition, a low range of the automatic gain control voltage V where the output power is set to medium power or low power (eg,
(0 to 0 volts), the ratio of the gain attenuation of the intermediate frequency amplifier 21 to the total gain attenuation is large (approximately 2).
/ 3 or more), so that C / N was deteriorated.
【0008】一方、受信回路における利得減衰特性は自
動利得制御電圧に対して直線的になるように設計されて
いるが、上述のように、RF増幅器23は自動利得制御
電圧Vが高くなると利得が飽和するので、自動利得制御
電圧Vと利得減衰量との関係(利得減衰特性)が直線的
にならず、その結果、全体の利得減衰特性(図5の曲線
C参照)も直線的にならず、受信回路における利得減衰
特性との整合が取れないという問題があった。On the other hand, the gain attenuation characteristic of the receiving circuit is designed to be linear with respect to the automatic gain control voltage. However, as described above, the RF amplifier 23 has a gain when the automatic gain control voltage V increases. Since the saturation occurs, the relationship between the automatic gain control voltage V and the amount of gain attenuation (gain attenuation characteristic) is not linear, and as a result, the overall gain attenuation characteristic (see curve C in FIG. 5) is not linear. However, there is a problem that matching with the gain attenuation characteristic in the receiving circuit cannot be achieved.
【0009】そこで、本発明の送信回路は、低出力電力
時(自動利得制御電圧Vの高い範囲(例えば3.0ボル
ト〜1.5ボルト))におけるS/Nや、中低電力出力
時(自動利得電圧Vの低い範囲(例えば1.5〜0ボル
ト))におけるC/Nを改善し、さらに、利得減衰特性
を直線的にすることを目的とする。Therefore, the transmission circuit of the present invention provides an S / N at low output power (high range of the automatic gain control voltage V (for example, 3.0 volts to 1.5 volts)) or a medium-low power output ( It is an object of the present invention to improve the C / N in a low range of the automatic gain voltage V (for example, 1.5 to 0 volt) and to make the gain attenuation characteristic linear.
【0010】[0010]
【課題を解決するための手段】上記の課題を解決するた
め、本発明の送信回路は、中間周波信号を増幅する中間
周波増幅器と、前記中間周波信号を前記中間周波信号よ
りも周波数が高い送信信号に周波数変換する周波数変換
器と、前記送信信号を増幅する高周波増幅器と、前記高
周波増幅器で増幅された送信信号をさらに増幅するとと
もに電力増幅器に入力する駆動増幅器とを備え、前記中
間周波増幅器と前記高周波増幅器と前記駆動増幅器とを
可変利得増幅器で構成し、自動利得制御電圧によって前
記中間周波増幅器の利得と前記高周波増幅器の利得と前
記駆動増幅器の利得とを変えるようにした。In order to solve the above-mentioned problems, a transmitting circuit according to the present invention comprises an intermediate frequency amplifier for amplifying an intermediate frequency signal, and a transmitting circuit for transmitting the intermediate frequency signal having a higher frequency than the intermediate frequency signal. A frequency converter for frequency-converting the signal, a high-frequency amplifier for amplifying the transmission signal, and a drive amplifier for further amplifying the transmission signal amplified by the high-frequency amplifier and inputting to the power amplifier; The high-frequency amplifier and the drive amplifier are constituted by variable gain amplifiers, and the gain of the intermediate frequency amplifier, the gain of the high-frequency amplifier, and the gain of the drive amplifier are changed by an automatic gain control voltage.
【0011】また、本発明の送信回路は、前記自動利得
制御電圧は第一の電圧から第二の電圧まで変化し、前記
中間周波増幅器の利得および前記高周波増幅器の利得は
前記第一の電圧と前記第二の電圧との間で変化して前記
第一の電圧でそれぞれ最大利得になるとともに前記第二
の電圧でそれぞれ最小利得となり、前記駆動増幅器の利
得は前記自動利得制御電圧が前記第一の電圧から前記第
一の電圧と前記第二の電圧との間の第三の電圧まで変化
するに従って最大利得から所定の利得まで暫時減衰し、
前記第三の電圧と前記第二の電圧の間では前記所定の利
得を保持するようにした。Further, in the transmission circuit according to the present invention, the automatic gain control voltage varies from a first voltage to a second voltage, and the gain of the intermediate frequency amplifier and the gain of the high frequency amplifier are different from the first voltage. It changes between the second voltage and reaches the maximum gain at the first voltage and the minimum gain at the second voltage respectively, and the gain of the driving amplifier is such that the automatic gain control voltage is equal to the first gain. Attenuated temporarily from a maximum gain to a predetermined gain as it changes from the voltage of the first voltage to a third voltage between the second voltage,
The predetermined gain is maintained between the third voltage and the second voltage.
【0012】また、本発明の送信回路は、前記駆動増幅
器は増幅素子を有する増幅回路と前記増幅素子に電流を
流す定電流回路とで構成され、前記増幅回路の利得は前
記電流に比例し、前記定電流回路の電流は前記自動利得
制御電圧が前記第一の電圧から前記第三の電圧まで変化
するに従って最大電流から所定の電流まで暫時減少し、
前記第三の電圧と前記第二の電圧との間では前記所定の
電流を保持するようにした。Further, in the transmission circuit according to the present invention, the drive amplifier includes an amplifier circuit having an amplifier element and a constant current circuit for flowing a current to the amplifier element, wherein the gain of the amplifier circuit is proportional to the current; The current of the constant current circuit temporarily decreases from a maximum current to a predetermined current as the automatic gain control voltage changes from the first voltage to the third voltage,
The predetermined current is maintained between the third voltage and the second voltage.
【0013】また、本発明の送信回路は、前記定電流回
路は二つのトランジスタを有するカレントミラー回路と
前記トランジスタの電流を制御するジャンクションFE
Tとで構成され、前記トランジスタの一方に流れる電流
を前記増幅素子に流し、前記トランジスタの他方のコレ
クタには抵抗を介して固定の電圧を供給するとともに前
記ジャンクションFETのソースを接続し、前記ジャン
クションFETのゲートに前記自動利得制御電圧を供給
した。In the transmission circuit according to the present invention, the constant current circuit may include a current mirror circuit having two transistors and a junction FE for controlling the current of the transistors.
T, a current flowing through one of the transistors flows through the amplifying element, a fixed voltage is supplied to the other collector of the transistor via a resistor, and a source of the junction FET is connected. The automatic gain control voltage was supplied to the gate of the FET.
【0014】[0014]
【発明の実施の形態】本発明の送信回路を図1乃至図3
に従って説明する。図1は本発明の送信回路のブロック
構成図、図2は図1に示すブロック構成図における中間
周波増幅器、RF増幅器、ドライバ増幅器の利得減衰特
性図、図3は図1におけるドライバ増幅器の回路図であ
る。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A transmitting circuit according to the present invention is shown in FIGS.
It will be described according to. FIG. 1 is a block diagram of a transmission circuit of the present invention, FIG. 2 is a diagram of gain attenuation characteristics of an intermediate frequency amplifier, an RF amplifier, and a driver amplifier in the block diagram of FIG. 1, and FIG. 3 is a circuit diagram of a driver amplifier in FIG. It is.
【0015】先ず、図1において、QPSK変調された
200MHz帯の中間周波信号IFは図示しない変調器
から出力されて中間周波増幅器1に入力される。中間周
波増幅器1は利得制御が可能な可変利得増幅器で構成さ
れ、その利得は基地局からのパワーコントロール信号に
基づく自動利得制御電圧Vによって制御される。自動利
得制御電圧Vは、第一の電圧である3.0ボルトから第
二の電圧である0ボルトまで変化する。そして、中間周
波増幅器の利得は自動利得制御電圧Vが3.0ボルトの
ときに最大となり、0ボルトのときに最小となる。従っ
て、図2の曲線Aに示すように、自動利得制御電圧Vが
3.0ボルトから0ボルトに変化するに従っておよそ6
0dBまで減衰するように制御される。この自動利得制
御電圧Vは受信信号のレベルの高低の方向に対して0ボ
ルトから3.0ボルトまで変化する。中間周波信号IF
は中間周波増幅器1によって増幅された後、混合器2a
と局部発振器2bとで構成される周波数変換器2に入力
される。中間週波信号IFは局部発振器2bから出力さ
れる局部発振信号と混合器2aにおいて混合されておよ
そ1.1GHz帯の送信信号RFに周波数変換される。First, in FIG. 1, a 200 MHz band intermediate frequency signal IF subjected to QPSK modulation is output from a modulator (not shown) and input to an intermediate frequency amplifier 1. The intermediate frequency amplifier 1 is composed of a variable gain amplifier whose gain can be controlled, and its gain is controlled by an automatic gain control voltage V based on a power control signal from a base station. The automatic gain control voltage V changes from a first voltage of 3.0 volts to a second voltage of 0 volt. The gain of the intermediate frequency amplifier becomes maximum when the automatic gain control voltage V is 3.0 volts, and becomes minimum when the automatic gain control voltage V is 0 volts. Therefore, as shown by curve A in FIG. 2, as the automatic gain control voltage V changes from 3.0 volts to 0 volts,
It is controlled to attenuate to 0 dB. The automatic gain control voltage V changes from 0 volts to 3.0 volts in the direction of the level of the received signal. Intermediate frequency signal IF
Is amplified by the intermediate frequency amplifier 1 and then mixed by the mixer 2a.
And a local oscillator 2b. The intermediate frequency signal IF is mixed with a local oscillation signal output from the local oscillator 2b in the mixer 2a and frequency-converted into a transmission signal RF in a band of about 1.1 GHz.
【0016】送信信号RFは、先ず、高周波増幅器(R
F増幅器という)3で増幅される。RF増幅器3も利得
制御が可能な可変利得増幅器で構成され、その利得は自
動利得制御電圧Vが3.0ボルトで最大となり、0ボル
トで最小となる。そして、図2の曲線Bに示すように、
自動利得制御電圧Vによっておよそ30dBまで減衰が
可能に制御される。しかし、RF増幅器3の利得は、図
2の曲線Bに示すように、利得制御電圧Vが1.5ボル
トより高くなるに従って飽和する傾向となっている。R
F増幅器3で増幅された送信信号RFは駆動増幅器(ド
ライバ増幅器という)4でさらに増幅される。ドライバ
増幅器4は次段の電力増幅器5を十分に駆動できるレベ
ルまで送信信号RFを増幅するためのものである。The transmission signal RF is first transmitted to a high-frequency amplifier (R
(Referred to as an F amplifier) 3. The RF amplifier 3 is also constituted by a variable gain amplifier capable of gain control, and its gain becomes maximum when the automatic gain control voltage V is 3.0 volts, and becomes minimum when the automatic gain control voltage V is 0 volts. Then, as shown by a curve B in FIG.
The automatic gain control voltage V controls the attenuation to about 30 dB. However, the gain of the RF amplifier 3 tends to saturate as the gain control voltage V becomes higher than 1.5 volts, as shown by the curve B in FIG. R
The transmission signal RF amplified by the F amplifier 3 is further amplified by a driving amplifier (referred to as a driver amplifier) 4. The driver amplifier 4 is for amplifying the transmission signal RF to a level at which the power amplifier 5 at the next stage can be sufficiently driven.
【0017】また、ドライバ増幅器4も利得制御が可能
な可変利得増幅器で構成され、その利得は自動利得制御
電圧Vによって制御される。しかし、その利得を制御す
る自動利得制御電圧Vの範囲は、3.0ボルトから3.
0ボルトと0ボルトの間の第三の電圧である1.5ボル
トまでの範囲に制限されている。そして、図2の曲線C
に示すように、自動利得制御電圧Vが1.5Vに低下す
るまでは所定の利得となるおよそ12dBまで減衰し、
自動利得制御電圧Vがそれ以下に低下しても一定の利得
減衰量12dBの状態を保持するようになっている。従
って、中間周波増幅器1とRF増幅器3とドライバ増幅
器4とによる全体の利得減衰量は図2の曲線Dに示すよ
うに、およそ102dBまで変化する。この結果、全体
の利得減衰量に占める中間周波増幅器1の利得減衰量の
割合が少なくなってS/Nが良くなる。ドライバ増幅器
4によって増幅された送信信号RFは電力増幅器5によ
って所定の送信レベルまで増幅され、アンテナ6から基
地局に向けて送信される。The driver amplifier 4 is also constituted by a variable gain amplifier whose gain can be controlled, and its gain is controlled by an automatic gain control voltage V. However, the range of the automatic gain control voltage V for controlling the gain is 3.0 volts to 3.0 volts.
It is limited to a range of up to 1.5 volts, a third voltage between 0 and 0 volts. Then, the curve C in FIG.
As shown in the figure, the automatic gain control voltage V is attenuated to about 12 dB, which is a predetermined gain, until the automatic gain control voltage V decreases to 1.5 V,
Even if the automatic gain control voltage V drops below that level, a state of a constant gain attenuation of 12 dB is maintained. Therefore, the total gain attenuation by the intermediate frequency amplifier 1, the RF amplifier 3, and the driver amplifier 4 changes to about 102 dB as shown by the curve D in FIG. As a result, the ratio of the gain attenuation of the intermediate frequency amplifier 1 to the total gain attenuation is reduced, and the S / N is improved. The transmission signal RF amplified by the driver amplifier 4 is amplified to a predetermined transmission level by the power amplifier 5 and transmitted from the antenna 6 to the base station.
【0018】ドライバ増幅器4は、図3に示すように、
増幅回路となる差動増幅回路7と、定電流回路8とで構
成されている。差動増幅回路7は増幅素子である二つの
トランジスタ7a、7bを有し、それらのエミッタが互
いに接続され、コレクタには負荷抵抗7c、7dを介し
て電圧Bが供給される。そして、トランジスタ7c、7
dのエミッタに定電流回路8が接続される。送信信号R
Fはトランジスタ7a、7bのベース間に入力され、増
幅された送信信号RFはコレクタ間から出力される。な
お、増幅回路7の利得はトランジスタ7a、7bに流れ
るコレクタ電流にほぼ比例する。The driver amplifier 4 includes, as shown in FIG.
It comprises a differential amplifier circuit 7 serving as an amplifier circuit and a constant current circuit 8. The differential amplifying circuit 7 has two transistors 7a and 7b as amplifying elements, their emitters are connected to each other, and a voltage is supplied to a collector via load resistors 7c and 7d. Then, the transistors 7c and 7
The constant current circuit 8 is connected to the emitter of d. Transmission signal R
F is input between the bases of the transistors 7a and 7b, and the amplified transmission signal RF is output from between the collectors. Note that the gain of the amplifier circuit 7 is substantially proportional to the collector current flowing through the transistors 7a and 7b.
【0019】定電流回路8はカレントミラー回路9と電
流制御回路10で構成される。カレントミラー回路9を
構成する一方のトランジスタ9aのコレクタが差動増幅
回路7のトランジスタ7a、7bのエミッタに接続され
る。また、カレントミラー回路9を構成する他方のトラ
ンジスタ9bのコレクタとベースとが互いに接続され、
そのコレクタには抵抗9cを介して電圧Bが供給され
る。また、電流制御回路10を構成するジャンクション
FET10aのドレインに電圧Bが供給され、ソースが
抵抗10bによってトランジスタ9bのコレクタに接続
される。そして、ゲートに自動利得制御電圧Vが供給さ
れる。なお、トランジスタ9a、9bのエミッタはグラ
ンドに接続される。The constant current circuit 8 includes a current mirror circuit 9 and a current control circuit 10. The collector of one transistor 9a constituting the current mirror circuit 9 is connected to the emitters of the transistors 7a and 7b of the differential amplifier circuit 7. Also, the collector and base of the other transistor 9b constituting the current mirror circuit 9 are connected to each other,
The voltage B is supplied to the collector via the resistor 9c. The voltage B is supplied to the drain of the junction FET 10a constituting the current control circuit 10, and the source is connected to the collector of the transistor 9b by the resistor 10b. Then, the automatic gain control voltage V is supplied to the gate. Note that the emitters of the transistors 9a and 9b are connected to the ground.
【0020】以上の構成において、カレントミラー回路
9における他方のトランジスタ9bのコレクタ電流は抵
抗9cに流れる電流とジャンクションFET10aに流
れる電流とが加算された電流であり、抵抗9cに流れる
電流はほぼ一定であるが、ジャンクションFET10a
に流れる電流は自動利得制御電圧Vによって変化する。
従って、トランジスタ9bのコレクタ電流は自動利得制
御電圧Vが3.0ボルトで最大となる。カレントミラー
回路9のトランジスタ9aのコレクタ電流はトランジス
タ9bのコレクタ電流とは同じであるので、差動増幅回
路7の各トランジスタ7a、7bのエミッタにはその1
/2の最大電流が流れる。In the above configuration, the collector current of the other transistor 9b in the current mirror circuit 9 is the sum of the current flowing through the resistor 9c and the current flowing through the junction FET 10a, and the current flowing through the resistor 9c is substantially constant. There is a junction FET 10a
The current flowing through the power supply changes depending on the automatic gain control voltage V.
Therefore, the collector current of the transistor 9b becomes maximum when the automatic gain control voltage V is 3.0 volts. Since the collector current of the transistor 9a of the current mirror circuit 9 is the same as the collector current of the transistor 9b, the emitter of each of the transistors 7a and 7b of the differential amplifier circuit 7 has one of them.
/ 2 maximum current flows.
【0021】そして、自動利得制御電圧Vが3.0ボル
トのときは差動増幅回路7のトランジスタ7a、7bに
最大電流が流れて差動増幅回路の利得が高くなり、図2
の曲線Cに示すように、自動利得制御電圧Vが低下する
に従って差動増幅回路7のトランジスタ7a、7bに流
れる電流が減少して利得が低下する。そして、自動利得
制御電圧Vが第三の電圧である1.5ボルトになるとジ
ャンクションFET10aがカットオフとなるようにな
っており、このときにはジャンクションFET10aに
は電流が流れなくなり、カレントミラ回路9のトランジ
スタ9bには抵抗9cから流れる所定の電流のみが流
れ、差動増幅回路の利得はおよそ12dB減衰したとこ
ろで一定となる(図2曲線C参照)。なお、差動増幅回
路7は、ジャンクションFET10aのゲート電圧が
3.0ボルト以上になった場合にはさらに利得が上昇す
るようになっている。When the automatic gain control voltage V is 3.0 volts, the maximum current flows through the transistors 7a and 7b of the differential amplifier circuit 7 to increase the gain of the differential amplifier circuit.
As shown by the curve C, as the automatic gain control voltage V decreases, the current flowing through the transistors 7a and 7b of the differential amplifier circuit 7 decreases, and the gain decreases. When the automatic gain control voltage V reaches the third voltage of 1.5 volts, the junction FET 10a is cut off. At this time, no current flows through the junction FET 10a, and the transistor of the current mirror circuit 9 Only a predetermined current flowing from the resistor 9c flows through 9b, and the gain of the differential amplifier circuit becomes constant when the gain is attenuated by about 12 dB (see curve C in FIG. 2). The gain of the differential amplifier circuit 7 further increases when the gate voltage of the junction FET 10a becomes 3.0 volts or more.
【0022】この結果、中間周波増幅器1の利得とRF
増幅器3の利得とは自動利得制御電圧Vが3.0ボルト
から0ボルトに低下するに従って暫時低下し、一方、ド
ライバ増幅器4の利得は自動利得制御電圧Vが3.0ボ
ルトから1.5ボルトに低下するに従って暫時低下し、
1.5ボルト以下になるとほぼ一定の減衰量(12d
B)に固定される。この結果、自動利得制御電圧が1.
5ボルト以上の範囲ではドライバ増幅器4の利得減衰特
性が加算されるので、RF増幅器3の飽和特性が補正さ
れて、全体の利得減衰特性は、図2の曲線Dに示すよう
に、直線的となる。As a result, the gain of the intermediate frequency amplifier 1 and the RF
The gain of the amplifier 3 temporarily decreases as the automatic gain control voltage V decreases from 3.0 volts to 0 volt, while the gain of the driver amplifier 4 changes from 3.0 volts to 1.5 volts of the automatic gain control voltage. Falls for a while as it falls,
When the voltage falls below 1.5 volts, the attenuation is almost constant (12 d
B). As a result, the automatic gain control voltage becomes 1.
In the range of 5 volts or more, the gain attenuation characteristic of the driver amplifier 4 is added, so that the saturation characteristic of the RF amplifier 3 is corrected, and the overall gain attenuation characteristic becomes linear as shown by a curve D in FIG. Become.
【0023】[0023]
【発明の効果】以上のように、本発明の送信回路は、中
間周波増幅器と高周波増幅器と駆動増幅器とを可変利得
増幅器で構成し、自動利得制御電圧によって中間周波増
幅器の利得と高周波増幅器の利得と駆動増幅器の利得と
を変えるようにしたので、全体の利得減衰量に占める中
間周波増幅器の利得減衰量の割合が少なくなってS/N
およびC/Nが良くなる。As described above, in the transmission circuit of the present invention, the intermediate frequency amplifier, the high frequency amplifier and the drive amplifier are constituted by variable gain amplifiers, and the gain of the intermediate frequency amplifier and the gain of the high frequency amplifier are controlled by the automatic gain control voltage. And the gain of the drive amplifier are changed, so that the ratio of the gain attenuation of the intermediate frequency amplifier to the total gain attenuation is reduced and the S / N ratio is reduced.
And C / N are improved.
【0024】また、本発明の送信回路は、駆動増幅器の
利得は自動利得制御電圧が第一の電圧から第一の電圧と
第二の電圧との間の第三の電圧まで変化するに従って最
大利得から所定の利得まで暫時減衰し、第三の電圧と第
二の電圧の間では所定の利得を保持するようにしたの
で、自動利得制御電圧に対する全体の利得減衰特性が直
線的になる。Further, in the transmission circuit of the present invention, the gain of the driving amplifier has a maximum gain as the automatic gain control voltage changes from the first voltage to a third voltage between the first voltage and the second voltage. To a predetermined gain, and the predetermined gain is maintained between the third voltage and the second voltage, so that the overall gain attenuation characteristic with respect to the automatic gain control voltage becomes linear.
【0025】また、本発明の送信回路は、駆動増幅器の
増幅素子に電流を流す定電流回路の電流は自動利得制御
電圧が第一の電圧から第三の電圧まで変化するに従って
最大電流から所定の電流まで暫時減少し、第三の電圧と
前記第二の電圧との間では所定の電流を保持するように
したので、その間では駆動増幅器の利得を所定の利得に
保持できる。Further, in the transmission circuit according to the present invention, the current of the constant current circuit for flowing the current to the amplifying element of the drive amplifier is changed from the maximum current to the predetermined current as the automatic gain control voltage changes from the first voltage to the third voltage. Since the current is temporarily reduced and the predetermined current is maintained between the third voltage and the second voltage, the gain of the drive amplifier can be maintained at the predetermined gain during that time.
【0026】また、本発明の送信回路は、定電流回路は
二つのトランジスタを有するカレントミラー回路とトラ
ンジスタの電流を制御するジャンクションFETとで構
成され、トランジスタの一方に流れる電流を増幅素子に
流し、トランジスタの他方のコレクタには抵抗を介して
固定の電圧を供給するとともにジャンクションFETの
ソースを接続し、ジャンクションFETのゲートに自動
利得制御電圧を供給したので、駆動増幅器の増幅素子に
流す電流を自動利得制御電圧によって制御できる。Further, in the transmission circuit according to the present invention, the constant current circuit is constituted by a current mirror circuit having two transistors and a junction FET for controlling the current of the transistor. A fixed voltage was supplied to the other collector of the transistor via a resistor, and the source of the junction FET was connected.The automatic gain control voltage was supplied to the gate of the junction FET. It can be controlled by the gain control voltage.
【図1】本発明の送信回路のブロック構成図である。FIG. 1 is a block diagram of a transmission circuit according to the present invention.
【図2】図1に示すブロック構成図における中間周波増
幅器、RF増幅器、ドライバ増幅器の利得制御特性図で
ある。FIG. 2 is a gain control characteristic diagram of an intermediate frequency amplifier, an RF amplifier, and a driver amplifier in the block configuration diagram shown in FIG.
【図3】図1における駆動増幅器の回路図である。FIG. 3 is a circuit diagram of the drive amplifier in FIG. 1;
【図4】従来の送信回路のブロック構成図である。FIG. 4 is a block diagram of a conventional transmission circuit.
【図5】図4に示すブロック構成図における中間周波増
幅器、RF増幅器、ドライバ増幅器の利得制御特性図で
ある。5 is a gain control characteristic diagram of an intermediate frequency amplifier, an RF amplifier, and a driver amplifier in the block diagram shown in FIG. 4;
【図6】図4における駆動増幅器の回路図である。FIG. 6 is a circuit diagram of the drive amplifier in FIG.
1 中間周波増幅器 2 周波数変換器 2a 混合器 2b 局部発振器 3 RF増幅器 4 ドライバ増幅器 5 電力増幅器 6 アンテナ 7 差動増幅器 7a、7b 増幅用トランジスタ 7c、7d 負荷抵抗 8 電流制御回路 9 カレントミラー回路 9a、9b トランジスタ 9c 抵抗 10 電流制限回路 10a ジャンクションFET 10b 抵抗 DESCRIPTION OF SYMBOLS 1 Intermediate frequency amplifier 2 Frequency converter 2a Mixer 2b Local oscillator 3 RF amplifier 4 Driver amplifier 5 Power amplifier 6 Antenna 7 Differential amplifier 7a, 7b Amplification transistor 7c, 7d Load resistance 8 Current control circuit 9 Current mirror circuit 9a, 9b transistor 9c resistor 10 current limiting circuit 10a junction FET 10b resistor
Claims (4)
と、前記中間周波信号を前記中間周波信号よりも周波数
が高い送信信号に周波数変換する周波数変換器と、前記
送信信号を増幅する高周波増幅器と、前記高周波増幅器
で増幅された送信信号をさらに増幅するとともに電力増
幅器に入力する駆動増幅器とを備え、前記中間周波増幅
器と前記高周波増幅器と前記駆動増幅器とを可変利得増
幅器で構成し、自動利得制御電圧によって前記中間周波
増幅器の利得と前記高周波増幅器の利得と前記駆動増幅
器の利得とを変えるようにしたことを特徴とする送信回
路。1. An intermediate frequency amplifier for amplifying an intermediate frequency signal, a frequency converter for converting the frequency of the intermediate frequency signal into a transmission signal having a higher frequency than the intermediate frequency signal, and a high frequency amplifier for amplifying the transmission signal. A driving amplifier for further amplifying the transmission signal amplified by the high-frequency amplifier and inputting the signal to a power amplifier, wherein the intermediate frequency amplifier, the high-frequency amplifier, and the driving amplifier are configured by variable gain amplifiers, and automatic gain control is performed. A transmission circuit, wherein a gain of the intermediate frequency amplifier, a gain of the high frequency amplifier, and a gain of the drive amplifier are changed depending on a voltage.
第二の電圧まで変化し、前記中間周波増幅器の利得およ
び前記高周波増幅器の利得は前記第一の電圧と前記第二
の電圧との間で変化して前記第一の電圧でそれぞれ最大
利得になるとともに前記第二の電圧でそれぞれ最小利得
となり、前記駆動増幅器の利得は前記自動利得制御電圧
が前記第一の電圧から前記第一の電圧と前記第二の電圧
との間の第三の電圧まで変化するに従って最大利得から
所定の利得まで暫時減衰し、前記第三の電圧と前記第二
の電圧の間では前記所定の利得を保持するようにしたこ
とを特徴とする請求項1記載の送信回路。2. The automatic gain control voltage changes from a first voltage to a second voltage, and the gain of the intermediate frequency amplifier and the gain of the high frequency amplifier are different from the first voltage and the second voltage. And the maximum gain at the first voltage and the minimum gain at the second voltage respectively, and the gain of the drive amplifier is such that the automatic gain control voltage is the first gain from the first voltage. As the voltage changes to a third voltage between the voltage and the second voltage, the voltage temporarily attenuates from a maximum gain to a predetermined gain, and holds the predetermined gain between the third voltage and the second voltage. The transmission circuit according to claim 1, wherein
回路と前記増幅素子に電流を流す定電流回路とで構成さ
れ、前記増幅回路の利得は前記電流に比例し、前記定電
流回路の電流は前記自動利得制御電圧が前記第一の電圧
から前記第三の電圧まで変化するに従って最大電流から
所定の電流まで暫時減少し、前記第三の電圧と前記第二
の電圧との間では前記所定の電流を保持するようにした
ことを特徴とする請求項2記載の送信回路。3. The drive amplifier includes an amplifier circuit having an amplifier element and a constant current circuit for flowing a current through the amplifier element. The gain of the amplifier circuit is proportional to the current, and the current of the constant current circuit is As the automatic gain control voltage changes from the first voltage to the third voltage, it temporarily decreases from a maximum current to a predetermined current, and the predetermined voltage is between the third voltage and the second voltage. 3. The transmission circuit according to claim 2, wherein a current is held.
有するカレントミラー回路と前記トランジスタの電流を
制御するジャンクションFETとで構成され、前記トラ
ンジスタの一方に流れる電流を前記増幅素子に流し、前
記トランジスタの他方のコレクタには抵抗を介して固定
の電圧を供給するとともに前記ジャンクションFETの
ソースを接続し、前記ジャンクションFETのゲートに
前記自動利得制御電圧を供給したことを特徴とする請求
項3記載の送信回路。4. The constant current circuit includes a current mirror circuit having two transistors and a junction FET for controlling a current of the transistor. A current flowing to one of the transistors flows to the amplifying element, 4. The transmission according to claim 3, wherein a fixed voltage is supplied to the other collector via a resistor, a source of the junction FET is connected, and the automatic gain control voltage is supplied to a gate of the junction FET. circuit.
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP30893198A JP3607097B2 (en) | 1998-10-29 | 1998-10-29 | Transmitter circuit |
US09/426,618 US6647072B1 (en) | 1998-10-29 | 1999-10-26 | Transmitting circuit improving SN ratio in low output power and CN ratio in low to intermediate output power |
KR1019990046995A KR100360358B1 (en) | 1998-10-29 | 1999-10-28 | Transmission circuit |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP30893198A JP3607097B2 (en) | 1998-10-29 | 1998-10-29 | Transmitter circuit |
Publications (2)
Publication Number | Publication Date |
---|---|
JP2000138599A true JP2000138599A (en) | 2000-05-16 |
JP3607097B2 JP3607097B2 (en) | 2005-01-05 |
Family
ID=17987006
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP30893198A Expired - Fee Related JP3607097B2 (en) | 1998-10-29 | 1998-10-29 | Transmitter circuit |
Country Status (3)
Country | Link |
---|---|
US (1) | US6647072B1 (en) |
JP (1) | JP3607097B2 (en) |
KR (1) | KR100360358B1 (en) |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3592980B2 (en) * | 1999-06-29 | 2004-11-24 | 株式会社東芝 | Transmission circuit and wireless transmission device |
JP2002076805A (en) * | 2000-08-29 | 2002-03-15 | Sharp Corp | Agc amplifier circuit and receiver employing it |
US7107027B2 (en) * | 2001-11-29 | 2006-09-12 | Intel Corporation | Distributed transmitter automatic gain control |
US10150333B2 (en) * | 2004-04-01 | 2018-12-11 | Meggitt Aerospace Limited | Hubcap for aircraft wheel |
US7512183B2 (en) * | 2005-03-22 | 2009-03-31 | International Business Machines Corporation | Differential transmitter circuit |
CN102368870B (en) * | 2011-10-11 | 2013-03-06 | 波达通信设备(广州)有限公司 | Linear optimization method of multi-modulation microwave system emission link |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS59157576A (en) * | 1983-02-27 | 1984-09-06 | Anritsu Corp | Spectrum analyzer |
US5307512A (en) | 1991-06-03 | 1994-04-26 | Motorola, Inc. | Power control circuitry for achieving wide dynamic range in a transmitter |
JP2845253B2 (en) * | 1992-07-15 | 1999-01-13 | 日本電気株式会社 | Keyed pulse detection circuit |
JP3479405B2 (en) | 1996-03-29 | 2003-12-15 | アルプス電気株式会社 | Transmitter amplifier circuit |
-
1998
- 1998-10-29 JP JP30893198A patent/JP3607097B2/en not_active Expired - Fee Related
-
1999
- 1999-10-26 US US09/426,618 patent/US6647072B1/en not_active Expired - Fee Related
- 1999-10-28 KR KR1019990046995A patent/KR100360358B1/en not_active IP Right Cessation
Also Published As
Publication number | Publication date |
---|---|
KR100360358B1 (en) | 2002-11-13 |
KR20000035084A (en) | 2000-06-26 |
JP3607097B2 (en) | 2005-01-05 |
US6647072B1 (en) | 2003-11-11 |
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